Electrolysis of fused electrolytes.



H. c. M. INGEBERG. IELECTROLYSIS 0F FUSED ELEQTROLYTESI. 7 APPLICATION mzo ocr. 30.1911.

rammed Apr. 8, 1919.

TmTTan sTaTns PATENT o Tica.

HENRY CHARLES MORRIS INGEBERG, 0F SANDVIKEN, NEAR CHRISTIANIA, NORWAY,

ASSIGNOR TO NORSK HYDRO-ELEKTRISK "KVAEL'STOFAKTIESELSKAB, OF CHRIS- TIANIA, NORWAY.

ELECTROLYSIS OF FUSED ELECTROLYTES.

Patented Apr. 8, 1919.

Application filed October 30, 1917. Serial No. 199,353.

To all whom it may concern Be it known that I, HENRY CHARLES Mon- RIS INGEBERG, a subject of the King of bTorway, residing at Sandviken, near Christiania, in the Kingdom of Norway, have m vented certain new and useful Improvements in the Electrolysis of Fused Electrolytes:

and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which itappertains to make and use the same.

In the electrolysis of fused electrolytes great difficulties have been found to be connected with keeping the cathode products and anode products separated fronrone another so as to prevent them from agaln reacting with one another and thereby causing a decrease in the output. Such (lifliculties are present with fused electrolytes to a still greater degree than in connection with the electrolysis of aqueous solutions.

The fact is that the products, which are separated out at one electrode usually Wlll show a strong tendency to dlssolve n the electrolyte and to diffuse in the direction of the other electrode, where a more or less strong polarization effect is produced. Several methods have been tried to prevent or at least to reduce such difiusion. The bell method, porous diaphragms, the use of metallic intermediary electrodes and the like have been tried but the roblem cannot as yet be said to have been sol ved in a satisfactory manner. The bell method leads to losses of tension owing to the long distance for the passage of the current, and the, diffusion is not obviated. The diaphragms hitherto employed on account of their porosity are not able to efliciently prevent the diffusion.

The question therefore is to find a materlal which will allow of no diffusion, but which in spite thereof does not prevent the passage of the current and the electrolysls. I have now discovered that some second class conductors such as glass non-porous ceramic substances and other similar bodies comply with these conditions and that they for this reason can be employed with advantage as a separating layer in the electrolysis of fused substances.

When the electrolysis is carried into efl'ect at high temperatures it may happen that the separating material selected for the process is converted into a plastic or semi-liquid condition. In such case it is necessary to place the material on suitable supporting members, which are not attacked by the electrolyte. Iron wire netting may for instance be rolled into the glass (wire glass).

The material may also be employed in combination with pulverulent granular or porous substances for the purpose of preventing direct contact between electrolyzation products, which might have been carried along by means of convection and the separating layer. 4

As a consequence of the fact that the electrolysis is to take place in a fused electrolyte, it is necessary to previously heat the melt; when the temperature of the melt has reached the required degree, the material of the diaphragm (for instance glass) will begin to act as a conductor.

The invention may, for instance, be used in connection with the electrolysis of liquid. chlorid of sodium. In this instance a mixture of chlorids of sodium and potassium is suitably made use of. The mixture may, for example, consist of 44 parts by weight of chlorid of sodium and 56 parts by weight of chlorid of potassium.

The electrolysis maybe carried into effect in an apparatus arranged as shown in the accompanying drawing, in which A is a fireproof vessel made of iron, carbon or other suitable material capable of resisting the action of the melt. B is another vessel placed inside the; vessel 1h and acting as a diaphragm, thus forming an inner compartment F and an. outer compartment G separated by the diaphragm B. This diaphragm vessel in the described example consists of sodium glass, preferably normal glass. The thickness of the glass may be about 2-3 mm, preferably but not necessarily having a wire mesh reinforcement E. In the vessel B is placed the cathode C, while the anode D consists of a carbon cylinder surrounding the diaphragm vessel B. The catholyte as well as the anolyte consists of the above named mixture of chlorids, which melts at about 660 0., while the electrolysis takes place at about 700 C. A tension of about 7 to 10 volts will be suitable. The diaphragm material in this instance acts as an intermediate electrolyte,- the sodium ions acting as a carrier of the current.

When the invention is to be used in connection with the production of magnesium metal the process may, for instance, be carried into effect as follows:

The same apparatus as that above described may be used. In the anode compartment is contained a melt consisting of chlorids of sodium and potassium in equimolecular proportions. The cathode compartment contains a melt comprising an equimolecular mixture of chlorids of magnesium, potassium and sodium, to which 10 per cent. offluoridof sodium has been added. The electrolysis is effected at a temperature of about 700-750 (1., and under a tension of about 7 to 10 volts.

Zinc metal may be obtained by the electrolysis of chlorid of zinc by working, for

instance, as follows; reference being had to the drawing:

The anode is placed in the inner compartment F and the cathode in the outer compartment The resulting zinc metal collects at the bottom of the electrolyzer vessel, from whence it may be withdrawn. In the anode compartment is also employed a melt comprising an equimolecular mixture of chlorids of potassium and sodium, and in the cathode compartment a melt comprising an equimolecular mixture of chlorids of zinc, potassium and sodium, to which 10 per cent. fluorid of sodium has been added. The electrolysis is effected at about 700? (3., under a tension of about 7 to 10 volts.

When carrying the invention into effect the temperature in the melt is never raised 7 so high as to cause glass to become easily flowing. It will at most become soft and very tough, so that it will stick to the reinforcement E, and it will not sink down.

I claim:

1. In the electrolysis of fused, electrolytes, the process which comprises separating the catholyte and anolyte from one another by an intermediary electrolyte of non-porous material electrically-conductive whenheated.

2. In the electrolysis of fused electrolytes, the method of separating the catholyte and anolyte, which comprises inserting a layer of glass therebetween.

3. In the electrolysis of fused electrolytes, the method which comprises separating during the electrolysis under heat conditions the catholyte and anolyte by means of a nonporous material electrically conductive only when in a heated condition, and supporting said material in operative position.

4. In the electrolysis of fused electrolytes, the method which comprises separating the catholyte and anolyte by a layer of non-conductive material which becomes conductive when heated and which is capable of acting as an intermediate electrolyte, and supporting said materiahin operative position.

5. In the electrolysis of fused electrolytes, the method which comprises separating the catholyte and anolyte by'a layer of nonporous non conductive material rendered conductive when heated and capable of acting as an intermediate electrolyte and in combination with substances of a porous nature 6. In the electrolysis of fused electrolytes, the method which comprises separating the catholyte and anolyte by a mechanically supported layer of non-porous material rendered plastic by the heat of the fused electrolyte and capable of acting as an intermediate electrolyte.

' 7. In the electrolysis of fused electrolytes, the method which comprises separating the fused catholyte and anolyte by a mechanically supported layer of glass in plastic condition.

8. In the electrolysis of fused electrolytes, the method which comprises separating the catholyte and anolyte by a layer of wire glass.

9. A diaphragm for use in the electrolysis of fused electrolytes, which comprises a nonporous material substantially insoluble in the electrolyte, substantially non-conducting at atmospheric temperatures and which becomes conductive at the temperature of fusion of the electrolyte.

. 10. A diaphragm for use in the electrolysis of fused electrolytes, which comprises a non-porousmaterial substantially insoluble in the electrolyte, substantially non-conducting at atmospheric temperatures and which becomes conductive at the temperature of fusion of the electrolyte, and a nonfusible supporting means for the diaphragm material.

11. A diaphragm for use in the electrolysis of fused electrolytes, which comprises a non-porous material substantially insoluble in the electrolyte, substantially non-con-- ducting at atmospheric temperatures and which becomes plastic or semi-liquid at the electrolyzation temperature.

12. A diaphragm for use in the electrolysis of fused electrolytes, which comprises a non-porous material substantially insoluble in the electrolyte, substantially non-conducting at atmospheric temperatures and which becomes plastic or semi-liquid at the electrolyzation temperature, and a support for said material infusible at the electrolymy invention, I have signed my name in zation temperature. presence of two subscribing witnesses.

13. glass diaphragm for use in the elec- HENRY CHARLES MORRIS INGEBERG trolysis of fused electrolytes. 5 M. A wire-glass diaphragm for use. in the \Vitnesses:

electrolysis of fused electrolytes. C. FABRICIUS HANSEN,

In testimony that I claim the foregoing as M. W. KAHRS. 

